1. Department of Cardiothoracic Surgery, Guy's and St Thomas’ Hospital, London, UK
2. Centre for Health Informatics, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
3. National Institute for Cardiovascular Outcomes Research, Institute of Cardiovascular Science, University College London, London, UK
4. Department of Cardiothoracic Surgery, Manchester Academic Health Science Centre, University Hospital of South Manchester, Wythenshawe, UK
5. Department of Cardiothoracic Surgery, Morriston Hospital, Morriston, Swansea, UK
6. Department of Cardiothoracic Surgery North Staffordshire Royal Infirmary, University Hospital of North Staffordshire NHS Trust, Stoke-on-Trent, UK
7. Department of Cardiothoracic Surgery, Heart and Lung Centre, New Cross Hospital, Wolverhampton, UK
8. Department of Cardiothoracic Surgery, Lancashire Cardiac Centre, Victoria Hospital NHS Trust, Blackpool, UK
9. Department of Cardiothoracic Surgery, Hammersmith Hospital, London, UK
10. Department of Cardiothoracic Surgery, The Cardiothoracic Centre, Freeman Hospital, Newcastle upon Tyne, UK.